ahci: fix PORTS_IMPL override

If PORTS_IMPL register is zero, ahci initialize it to full mask
corresponding to nr_ports in the CAP register.  hpriv->cap, which is
initialized at the end of the function, is incorrectly used as value
of CAP causing ahci to always override PORTS_IMPL to 0x1 if it's zero.
Fix it.

This fixes a bug where early ich6 ahci can only access the first port.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/ahci.c

@@ -527,7 +527,7 @@ static void ahci_save_initial_config(struct pci_dev *pdev,
 
 	/* fixup zero port_map */
 	if (!port_map) {
-		port_map = (1 << ahci_nr_ports(hpriv->cap)) - 1;
+		port_map = (1 << ahci_nr_ports(cap)) - 1;
 		dev_printk(KERN_WARNING, &pdev->dev,
 			   "PORTS_IMPL is zero, forcing 0x%x\n", port_map);